GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"27288 results found.
- GRB 090423: GROND second epoch imaging and refined SED
- Detection of bright radio afterglow of GRB 090424 with the VLA
- GRB 090426: Enhanced Swift-XRT position
- GRB 090426, RIMOTS optical upper limits
- GRB 090426: TNT confimation of optical counterpart
- GRB 090426: Swift detection of a burst with an optical counterpart
- GRB090424: R-band detection (37.5 hrs post-burst), jet break?
- GRB 090424: MASTER-Net prompt optical limit
- VLA radio observation of high-z GRB 090423
- GRB090424: BVRI/R-band detection after 15 hrs burst
- GRB 090424: THO optical observations
- GRB 090424: GROND Observations of the Optical/NIR Afterglow
- GRB 090423: Swift/BAT spectral lag results
- GRB 090424 : TAOS optical detection
- GRB 090424 optical observations
- GRB 090424: Swift-XRT refined analysis
- GRB 090423: energetic, luminosity and jet break
- Swift/UVOT observations of GRB 090424
- GRB 090424: Enhanced Swift-XRT position
- GRB 090424: Swift-BAT refined analysis
- GRB 090424: Fermi GBM Observation
- GRB 090423: Fermi GBM observation
- GRB 090422: Fermi GBM observation
- GRB 090423: Ep,i - Eiso correlation
- GRB 090424: SDSS Galaxy at the Swift position
- GRB 090424: TNT optical observations
- GRB 090424: ROTSE-III Confimation of Optical Counterpart
- GRB 090424: Swift detection of a burst with an optical counterpart
- GRB 090423: Deep z-band upper limit and confirmation of photo-z
- GRB 090423: GROND detection and preliminary photo-z
- GRB 090423: Correction to NIR photometry
- GRB 090423: Swift-XRT refined analysis
- GRB090423 - Swift/UVOT upper limits.
- GRB 090423: NIR photometry and evidence for spectral break
- GRB 090422: Swift-XRT refined analysis
- GRB090423, RIMOTS optical upper limits
- GRB 090423: Enhanced Swift-XRT position
- GRB 090423: Swift-BAT refined analysis
- GRB 090422: Swift/UVOT Upper Limits
- GRB 090423: Faulkes Telescope South observations
- GRB 090418A: R and I band observation
- GRB 090423: Swift detection of a burst
- GRB 090422: Liverpool Telescope possible candidate
- GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
- GRB 090422: Swift-BAT refined analysis
- GRB 090422: Enhanced Swift-XRT position
- GRB 090422: Liverpool Telescope observations
- GRB 090422: Swift detection of a burst
- GRB 090418C: Fermi GBM Detection
- GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
- Swift-BAT trigger 349718 is not a burst
- GRB 090417B: Optical observation
- GRB 090418A: optical observations
- GRB 090419: Swift/UVOT Observations
- GRB 090418B: Faulkes Telescope North observations
- GRB 090418A: Swift/UVOT Observations
- GRB 090417B: Swift/UVOT Upper Limits
- GRB 090417B Correction to the BAT refined analysis position
- GRB 090419: Swift-XRT refined analysis
- Konus-Wind observation of GRB 090418B
- GRB 090419: GROND detection of afterglow candidate
- GRB 090419: Swift-BAT refined analysis
- VLA radio detection of GRB 090418
- VLA radio upper limit on GRB 090417B
- GRB 090419: Enhanced Swift-XRT position
- GRB 090418: Swift XRT refined analysis
- GRB 090418A: ROTSE-III Refined Analysis
- GRB 090419: Swift detection of a burst
- GRB 090418B: Detection of a bright burst from Swift-BAT slew data
- GRB 090418: Swift-BAT refined analysis
- GRB 090417B: Swift-XRT refined analysis
- GRB 090418: Enhanced Swift-XRT position
- GRB 090417B: Swift-BAT further refined analysis
- GRB 090418: PAIRITEL NIR detection
- GRB 090418: ROTSE-III Confirmation of Optical Counterpart
- GRB 090418: Swift detection of a burst with optical afterglow
- GRB 090417B: Liverpool Telescope observations
- GRB 090417B: Swift-BAT refined analysis
- GRB 090417A: Swift-BAT refined analysis
- GRB 090417B: Swift detection of a burst
- GRB 090417: 2MASS galaxy within BAT Localization
- GRB 090417: Swift detection of a short burst
- GRB 090412: Fermi GBM detection
- GRB 090411B: Fermi GBM detection
- GRB 090411A: Fermi GBM detection
- GRB 090410: Suzaku WAM observation of the prompt emission
- GRB 090410: Swift-BAT refined analysis
- GRB 090410: Swift detection of a burst
- GRB 090409: Fermi GBM detection
- Swift-BAT Trigger 348781 is not a GRB
- Swift-BAT Trigger 348720 is not a GRB
- GRB090408, RIMOTS optical upper limits
- Swift-BAT trigger 348781: almost certainly not a burst
- Fermi GBM Detection of a weak source
- GRB 090408B: MASTER II-Kourovka optical observations
- GRB 090408: Swift detection of a burst
- GRB 090407: Swift-XRT refined analysis
- GRB 090407: Swift UVOT Upper Limits
- GRB 090407: Enhanced Swift-XRT position
- GRB 090407: Swift-BAT refined analysis